Many attempts have been made continuously to fabricate devices through printing processes in the fields of electronics and displays in order to reduce the cost needed for processing and materials and to allow mass production with ease. Many academic workers have conducted intensive studies related to such direct printing technology.
For example, active studies have conducted to fabricate electronic devices, such as RF filters based on low temperature co-fired ceramic technology, humidity sensors, organic thin film transistors, etc., through roll or ink-jet printing.
However, ink-jet printing processes using liquid ink is not suitable for the fabrication of a micropattern with a scale of several micrometers to several tens micrometers because of variations in liquid ejection condition and ejection direction caused by a wetting phenomenon at a printer nozzle. Particularly, in the case of thin film transistors requiring precise alignment between patterns, there were problems in that the resultant devices may malfunction due to the alignment error.
To solve such problems, active studies have been conducted to develop a patterning method based on self-alignment of liquid ink on a substrate surface-treated with hydrophobic and hydrophilic regions. However, the above method includes a complicated process because it requires hydrophilic and hydrophobic pretreatment. Moreover, as shown in FIG. 1, additives having hydrophobic properties are diffused to the surface of a substrate during the heat treatment, thereby causing a so-called dewetting phenomenon of ink from the edges of the pattern.